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Poor fuel mileage after after EGR valve position sensor changed

9K views 19 replies 7 participants last post by  Phil G. 
#1 ·
I recently had a situation where my 6.0L "popped" and blew some black smoke ONCE.

I went to the dealer and they replaced the EGR valve position sensor and now the truck gets about 2-mpg LESS than before the repair.

The problem started immediately after I pick up the tuck.

The dealer says that "maybe" I need a new fuel filter, (three years old), but I am not confident that they are diagnosing it correctly.

It feels like they are shooting in the dark.

Any ideas about what is going on?
 
#2 ·
For clarification, what is a "EGR valve position sensor" is that the EBP sensor (exhaust back pressure) or something else?

Have you got a part #? that would help, I'm at a loss as to which sensor your speaking of.
 
#6 ·
OK, so that is the EBP sensor and that is a related piece to the EGR system that can cause smoking if it's not working, hopefully they removed the tube it's mounted in and cleaned the soot out of that at the same time.

Being it's a Ford dealer with the knowledge and the proper IDS scan tool, I have to think they are the best ones to find it for you IF their diesel mechanic has been around long enough to have worked on a bunch of 6.0L trucks, they are a bit unique.

I am not a diesel tech but I do all of the work on my own truck so I am by no means an authority on this but here's what I would be looking at with symptoms being smoking:

EPV valve
EGR Valve
MAP sensor
Turbo (sticking) or leaking in the IC pipes
Exhaust leaks in front of the turbo.
Injector contribution (ie: injector & FICM performance)
wiring related to above.

Maybe an expert will chime in with better info but that's the list I would work off of.
 
#5 ·
Here is the short - long story.
I have about 11K miles on a Ford remanufactured engine after the original 6.0L engine in my 2004, F250 BLEW UP (catastrophic failure) on I-78 while I was on the way to Hershey last October (144,720-miles).
I was luckily not towing at the time.
The $17K replacement was as I indicated a Ford remanufactured engine - long block (entire engine minus hang-on components).
So things went along relatively well until a few weeks ago when i was pulling out of an up hill side street and there was a POP and black smoke blew out of the exhaust.
Note that I had previously been curious about what appeared to be oil (unburnt diesel fuel?) on the outside of the exhaust pipe (may be unrelated).
I drove to the dealer and told them about the incident, but the truck seemed to run fine after the incident and I delayed an evaluation.
I later needed brake lines so I had them evaluate the previously reported problem which is when they installed the following parts: 4C3Z-9J460-A, and 5C3Z-12224-A.
Before the installation of the parts above, my fuel mileage was between 16.9 & 17.9 mpg, city driving.
It is now 14.0 to 14.5 mpg.
Now the dealer says that to begin diagnosis I need to replace the fuel filters (perhaps, 3-years-old).
I have run 1.5 tanks of fuel through the engine and added Lucas injector cleaner, in the hope that it would do something, but to no avail.
Is this adequate information?
What do you all think?
Thanks,
Peter
 
#7 ·
So the Dealer changed the fuel filters (2) and the fuel use went from 14.9 to 15.5 MPG.
That is not a big difference, considering that before they replaced the other parts shown above, the MPG was 16.9 to 17.9 combined city / highway driving.
I am still on the hunt for the cause of the problem.
I will run out this tank of fuel (just in case it was bad fuel - this tank is SUNOCO) before I report to the Dealer on the result of the fuel filter R&R and current MPG.
Their comments to date are that if there is no WARNING LIGHT showing, then a scan will not help.
I am perplexed at this significant change in MPG after the parts switch.
It makes no sense to me.
 
#8 ·
The question is, did they reset the PCM after changing the EGR? Any time a engine or emissions component is changed the PCM needs to be reset so it cam learn the new baseline readings. This also includes changing an exhaust component or doing a blue spring mod. Doing a code clear procedure will not work. Either the batteries need to be disconnected or pull the PCM keep alive fuse for 20 seconds which saves all the clock and radio settings. On some of the 04's and on the 05's and 06's it is fise number ten in the underhood fuse panel.
 
#9 ·
So, I just pulled the fuse for the PCM fuse UNDER THE DASH, #36 and took the BFT for a ride on the highway.
I kept the fuse out for longer than 20-seconds, but for not more than 45-seconds.
The fuel mileage inched its way up to 18-mpg, and I will see what the combined city / highway mileage looks like after a few days.
Typically, on the highway the BFT will get over 19-mpg, but with this test I started for a few miles on the city streets.
I will keep you informed.
Thanks for the lead on a possible solution.
 
#10 ·
i have driven through a full tank of fuel, both city and highway, and my fuel mileage is now at about 15.2 mpg.
I had pulled the PCM fuse and I was hopeful but to no avail.
Is it possible that the valves the dealer used were not correct for the Ford remanufactured engine?
Could the ERG on the remanufactured engine require different parts than what was originally on the 6.0 when it was new?
Is it possible that there was a factory upgrade on the ERG over time because the 6.0 had such problems with the ERG unit on the original engines?
I am at a loss to think what could cause this problem.
I am still atlas 2-mpg lower than before they did the parts replacement.
 
#13 ·
Yes, it is.

Do you have any other symptoms?
 
#14 ·
Are you sure the pop you heard was a inter cooler hose ripping a split in it. And now you have an air leak. That would hurt your mileage. Nothing would show up as codes. Your just losing boosted air back to the atmosphere. The split could be on the bottom side and you can't see it.
 
#16 ·
As for other symptoms, I might think that I have poor low-end acceleration, but it is subtle, so I am not sure on that matter.
There are no red flags waving at this time.
BTW, I did disconnect the batteries in addition to pulling the PCM fuse.
I did that yesterday a week after pulling and replacing the fuse (that did not help the mileage).
In the process of disconnection the batteries the CD Player now does not wrk (UGH!), but I understand that if I pull those fuses, it should totally reset.
One car or truck, one pain in the butt and I have one truck and three cars (UGH, UGH, UGH, UGH, HA!).
The fun doesn't stop!
 
#18 · (Edited)
Do you have the plastic intercooler to intake pipe or a metal one. Since you have a 2004 it is probably metal, but with the engine replacement it is worth checking. The plastic pipe on 2005 and up will fail and crack. You need to replace them with a kit that includes the metal tube and boots. Check both the silicone boots that attach the turbo to the CAC pipe to the intercooler and if you have the metal pipe from the intercooler to the intake check both of the boots on it. To check the boots look inside them while squeezing them to look for cracks.
 
#19 ·
The BFT is going back to the Dealer this week with the info this GREAT Forum provided.
The Dealer was willing to schedule the appointment after I walked in and reported that my MPG is now at between 13.6 and 14.6 MPG and I told them of the Forum's suggested problems.
I looked at the engine and turbo set-up after I received the last post, and although I am a competent wrench when it comes to my 1925 Pierce-Arrow, and sometimes with simple mechanical problems on my two (2) 1987 BMWs, I am "out to sea" when thinking about turning a wrench on a 6.0L Turbo Diesel engine.
This is such a useful Forum, I am blown away with the knowledge / expertise offered by Forum members to solve obscure / niggling / persistent / intermittent / pain-in-the-butt problems.
Many thanks!
 
#20 ·
good luck at the dealer. hopefully he can straighten a few things out for you
 
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